The presence or absence of food poisoning bacteria has been checked in the fields of food inspection, environmental inspection, clinical trial, animal health management, and the like. In recent years, a method that amplifies DNA contained in a sample by a polymerase chain reaction (PCR), and detect the target bacteria based on the amplified product has been employed.
Electrophoresis is widely used to detect food poisoning bacteria to determine the presence or absence of the target bacteria. The strain may be more accurately identified by purifying the detected amplified product, and performing a sequencing process.
However, the electrophoretic detection technique has a problem in that it is difficult to determine and identify the strain since it is difficult to identify bacteria having a similar amplification size. Moreover, the electrophoretic detection technique requires a complex operation such as gel preparation, and utilizes staining using a carcinogen (e.g., ethidium bromide). The electrophoretic detection technique also has a problem in that the sequencing process takes time, and requires an inconvenient operation.
Therefore, a detection technique using a DNA microarray has been used in recent years in addition to the electrophoretic detection technique. A probe that hybridizes to the target bacteria is immobilized on the DNA microarray. It is possible to determine the strain regardless of the amplification size by hybridizing the PCR amplified product to the probe. Moreover, the detection technique using the DNA microarray does not require staining using a carcinogen or the like, ensures prompt detection as compared with the sequencing process, and allows convenient operation.
A technique that detects the target bacteria by hybridizing the PCR amplified product to a probe by in situ hybridization or the like has also been used.
For example, Patent Document 1 discloses a probe and a DNA microarray that can detect Alicyclobacillus acidocaldarius, Bacillus caldotenax, Bacillus cereus, Bacillus subtilis, Thermoactinomyces vulgaris, and Staphylococcus epidermidis. 
Patent Document 2 discloses a probe that can detect food poisoning bacteria (e.g., Aeromonas bacteria, Listeria, Welsh bacteria, Vibrio parahaemolyticus, Salmonella, and enteropathogenic Escherichia coli), and a method that detects food poisoning bacteria by in situ hybridization using the probe.    Patent Document 1: JP-A-2008-200012    Patent Document 2: JP-A-2006-166912